At the time of their completion in 1929, the production plants at Herøya, near Porsgrunn, relied entirely on supplies of liquid ammonia by rail from Rjukan and Notodden. Ammonia was the nitrogen source for Hydro's production of mineral fertilizer.

The Rjukan railway was an ambitious project to provide a transport route to the coast so that raw materials could be brought in to and finished fertilizer products sent out from the Rjukan factories. Between 1909 and 1991, the Rjukan railway transported 30 million tonnes of goods - the equivalent of 1.5 million goods wagons. And the railway also provided the Rjukan community with passenger transport for many decades.

Train, ferry and barge

The route between Rjukan and Herøya was not simple. The Tinnsjø lake had to be crossed by railway ferry, and the last stretch - from Borgestad to Herøya - was by barge. There were plans for Porsgrunn to be linked to the railway network via Porsgrunn, but it took 23 years before the last tunnel was excavated and the link was fully established.

This rail connection was not only important for Hydro's operations, it also represented the most modern transport system at the time. The rail ferries crossing the Tinnsjø lake were the largest inland ferries the world had seen.

In 1909 the wooden ferry "Tinnsjø" started operation. During the winter it was towed by the tug and ice-breaker "Skarsfos". Later the ferries "Hydro", "Ammonia" and "Storegut" joined the force. The ferries were at work over the Tinnsjø lake right up until the early nineties.

The importance and vulnerability of this supply line was demonstrated a couple of times during the second World War. The most dramatic incident was the sabotage action against the ferry "Hydro" on 20 February, 1944 (LINK 1943). Apart from this and other actions during the war, transport between Rjukan and Herøya proceeded without any serious accidents or interruptions to traffic. 

Violent natural forces

There were however several incidents that illustrate the challenges of building a transport route through the dramatic scenery of Upper Telemark. Wagons were overturned several times by the down currents that can occur in the valley. Measures had to be taken to prevent the wind getting a hold beneath the wagons.

When ammonia and fertilizer production was discontinued at Rjukan, the ferries were taken over by a foundation, which takes care of maintenance and arranges tours for tourists in the summer.